Disposable absorbent articles, such as sanitary napkins, catamenial pads, pantiliners, diapers, training pants, incontinent garments, and the like, are designed to be worn adjacent to a human body to absorb discharged body fluids. The body fluids can include urine, blood, menses and other excrements discharged by the body at various times, such as during a bowel movement or during a menstrual period. Such articles are normally multilayered in construction and include a liquid-permeable cover, a liquid-impermeable baffle and a hydrophilic absorbent core positioned therebetween. The article can also include a transfer and/or distribution layer situated between the cover and the absorbent core which directs body fluid downward, away from the cover, and distributes the fluid in the x and y directions. The cover is designed to allow rapid transfer of body fluid down into the absorbent core, where it can be retained. The baffle serves to prevent fluid present in the absorbent core from leaking out of, and soiling or staining, an undergarment or another adjacent piece of clothing.
Numerous prior art patents exist which teach different materials and constructions for the cover layer. The initial use of nonwoven materials has evolved into the use of one or more nonwoven fibrous layers, along with a film layer containing apertures. U.S. Pat. Nos. 3,945,386; 3,965,906; 3,967,623; 3,994,299; 4,014,341; 4,323,069 and 4,324,246 teach such combinations. Other patents, such as U.S. Pat. Nos. 3,888,254 and 4,675,013, teach the use of a cover layer which is laminated to other fibrous sheets. U.S. Pat. No. 4,762,520 teaches forming a cover from a carded fiber fabric containing melt fibers sub-divided into parallel streaks. Other U.S. patents, such as U.S. Pat. Nos. 4,710,186; 4,755,413; 4,798,604 and 4,806,411, teach forming apertures in the cover. U.S. Pat. No. 4,333,465 teaches a cover comprised of a liquid-impermeable composite material having a liquid-permeable zone. Lastly, U.S. Pat. Nos. 3,676,242; 4,690,679; 4,725,473 and 4,878,974 teach various methods of making film and fiber composite cover materials by coextrusion, laminating, and the like.
Two patent applications filed by Kimberly-Clark Corporation, which relate to nonwoven webs, include U.S. Ser. No. 07/608,095, filed Nov. 1, 1990, by inventors H. K. Barnes et al., entitled "HYDRAULICALLY NEEDLED NONWOVEN PULP FIBER WEB", now U.S. Pat. No. 5,137,600, and U.S. Ser. No. 07/633,594, filed Dec. 21, 1990, by inventors C. Everhart et al., entitled "HIGH PULP CONTENT NONWOVEN COMPOSITE FABRIC", now abandoned.
Presently, some manufacturers are moving toward the use of two or more different kinds of materials for the cover in order to enhance the functionality of the cover layer. Published Japanese patent application 122,727 (1989) teaches a sanitary napkin which has a cover constructed of two different hydrophobic materials, both of which contain apertures. U.S. Pat. No. 4,285,342 issued to Mesek is somewhat similar except, instead of using two different kinds of materials, a large opening is formed in the cover layer of a diaper to enhance fluid flow into the absorbent core. U.K. patent 2,124,907 issued to Lloyd teaches a fabric bonded to a water-impermeable material, with both materials located on the bodyside surface of the absorbent device.
In order for an absorbent article to exhibit improved fluid management, it should utilize one or more layers located between the cover and the absorbent. Such layer(s) should assist in keeping the cover dry by directing body fluid downward, in the z direction, away from the cover. The layer(s) can also function to move the body fluid outward, in the x and y directions, so as to facilitate rapid fluid intake by the absorbent. U.S. Pat. No. 4,908,026 issued to Sukiennik et al. teaches the use of a flow zone control layer located beneath the cover for facilitating dispersion of body fluid along the length of the absorbent article, before allowing the fluid to pass into the absorbent. Other U.S. patents, which teach the use of a fluid transfer or a fluid distribution layer beneath the cover, include U.S. Pat. Nos. 4,397,644; 4,480,000; 4,519,799 and 4,798,603. These patents teach various materials and compositions for the transfer or distribution layer, which assist in directing the body fluid downward, into the absorbent.
Now, an absorbent article has been invented which exhibits improved fluid management.